Forming tool



13% 3- c. L. BRACKETT Clave LBmokett QZ M Patented Dec. 28, 1943 UNITEDSTATE s PATENT OFFICE FORMING TOOL Clare L. Brackett, Detroit, Mich.

Original application September 16. 1938 Serial No. 230,329. Divided andthis application July 20, 1942. Serial-No. 451,618

9 Claims.

a tool of this character which will distort the nut to a precise,predetermined shape in a single operation.

Other objects and advantages of the invention of the nut and are ofappreciable width, al though they may be otherwise arranged.

In producing the nut, the blank with its in tegral reducedfrusto-conical axial extension is bored and slotted and the entire axialextent 'of the resulting bore is thread tapped. As best shown in Figure1, this results in providing the fingers I! with arcuate inner faces I4threaded in continuation of the nut bore threads l5 and at the samehelix angle; the curvature of the I inner faces ll of the fingers beingin the radius will-bev apparent during the course of the followingdescription.

This application is a division of my cq-pending application, Serial No.230,329, filedSeptember 16, 1938, for Self-binding nuts.

In the accompanying drawing which forms a part of this specification andwherein like characters of reference denote like parts throughout:

Figure 1 is atop plan view of a nut prior to distortion of the grippingmembers;

Figure 2 is a top plan view of the nutafter the gripping members havebeen distorted by "the tool of this invention;

Figure 3 is an elevation, partly in section, of the nut shown in Figure2;

Figure 4 is an end view of the forming tool;

Figure 5 is an axial sectional view taken on line 5-5 of Figure 4 and,

Figure 6 is an elevation, partly in section, 11-

, lustrating the manner of applying the forming tool, it being shown indotted lines as fully applied over the nut fingers.

A nut made in accordance with my invention comprises a body H, hereshown as a hexagonal nut body, having the usual axial bore extendingtherethrough from its top to its bottom face and provided on its topfacewith an annular series of axially parallel spaced gripping members l2integral with the nut body and surrounding the bore- A convenient mannerof forming the gripping members is by providing a reduced axialextension on the top face of the nut as a frusto-conical portion havingits periphery concentric with them; axis, and then radially slotting theextension at a piuralityof spaced points in an axial direction from theouter end of the extension into the top face portion of the nut body. Asshown in Figure 1, the resulting structure disposes of the grippingmembers I2 as an annular series of arcuate fingers spaced apart by theradial slots I3. Preferably the slots lead from the center of each sideface of .the nut bore.

The fingers are of equal lengthand curvature. their outer faces It beingarcuately parallel to their inner faces and convergent with respect tothe axis of the nut. Thus, each finger is of the same depth or thicknessfrom its leading edge I! to its trailing edge l8 at any' point betweenits base and its top edge iii in a plane passed transverselytherethrough perpendicular to its inner face.

Following the initial formation of the nut as shown in Figure 1, inwhich the thread line parallels the nut axis throughout the nut bore andthe entire longitudinal extent of the inner face of each finger It, thefingers are distorted into the positions shown in Figure 2. Thisis-accomplished by bending the fingers radially inward in convergentrelation to the axis of the nut, with however, a greater degree of bendattheir trailing edges than at their leading edges.

As shown in Figure 3, this bending operation disposes the inner threadedfaces ll of the fingers at an incline upwardly and inwardly convergentto the axis of the nut from their bases to their top edges [9. Thedegree of inward bend is progressively increased from each leading edgeH to each trailing edge l8, as a result of which the angle ofinclination is progressively increased uniformly from the leading to thetrailing edge. Accordingly, the entire area of the inner face of eachfinger is brought inside the thread circle of the nut bore and with thetrailing top edge at a lesser radial distance from the'axis of the nutthan the leading top edge, both edges, however, lying within the threadcircle.

Due to the fact that the arcs of the inner faces of the fingers are inthe radius of the nut bore. the faces I will be eccentric to'the bore atall points above their bases, and increasingly eccentric from a pointjust above their base lines to their top edges.

The nut illustrated in Figures 1, 2, 3 and 6 is disclosed in detail inmy application referred to above, and need not be further describedhere.

with the gripping fingers The, distortion of the nut fingersispreferably accomplished by pressure application thereover of a forming.tool having a plurality of pressure faces corresponding in numbenangleand shape when in their deformed shape. As best illustrated .in Figures4 to 6, the tool comprises a cylindrical punch having an axial socket orbore 24 in its work engaging end opening to an inwardly taperedcountersunk recess formed in the workengaging endof the punch.

The annular plurality of arcuate-faces Ila corresponding in number-andlocation to the nut; fingers l2 and curved in the radius of the outerfaces I6 thereof. These faces I2a are eccentric with respect'to thepunch bore 24, and decreasingly, so from their outer to their inner endsaxially of the punch,

with their inner ends merging into the bore 24.-

Each face is inclined upwardly and inwardly from its outer endinconvergent relation to the punch axis and the angle of inclination isprogressively increased from one sideedge to the other, resulting: in anannular seriesof shoulders Ilahaving edge faces .25 extending radiallyand at diametrically opposedv points; theopposed pairs of suched'gefaces lying at all points in a common diametrical' plane extendingaxially of the punch. I I. I a

The faces l2a are of equal angle, shape, curvature and area, and thecorner edges of the shoulders Ila are at all points from'their outer totheir inner ends at a lesser radial distance from the axis of thepunchbore 2! than are corresponding, points along the other andincreasingly so from thelr'inner outer ends. 1

As shown best in Figure to their 5, the T shoulder faces 25 have theirsides tapered upwardly and inwardly of the punchat. slightly differentangles so that they are convergent at a point substantially coincidentwith the periphery of the bore 24 at a diametrically opposite and inwardpoint thereon.

3 By virtue of this arrangement each shoulder face width from its outerto its greater width 25 is of an appreciable I inner end with,. howver,a slightly at its outer end. I Y

. Inthe operation of defcrmingthe nut fingers the punch is forced downaxiallyover the nut fingers, as indicated in Figure 6, whereupon thefingers will be given their peculiar deformation as previouslydescribed. It should here be pointed out that the angle of inclinationof the punch faces IZa isgreater than the angle of inclination of theouter facesof the nut fingers, and as the major inclination occurs atthe shoulders Ila the nut fingers will be given a corresponding bend informing their trailing edge portions I8- An important feature of thetool 23 lies in the provision centering abutments entering the nut slotsl3 when the tool is moved into pressure engagement with a nut andbacking up the leading'edges I! of the nut fingers so that they cannotbe twisted or be forced to move radially outward with respect to thethread circle of the nut; As the faces 25 provide radial plane surfacesagainst which the leading fiat edges ll of the nut fingers abut, andfurther, as no relative rotation takes place between the nut and tool inthe forming operation, the leading edges of the nut fingers will remainin substantially radial planes'and each fin ger will be, in effect, bentcircumferentially'on a longitudinal axis at its leading edge.

While Figure 6 illustrates the forming tool as wall of the recess isformed with a side edges of the faces,

of the shoulder faces 25 which provide being moved axially intoengagement over a nut fixed on a suitable support, it is evident that iffound desirable the nut may be moved relative to the forming tool or toa die having the same formative facing. Either the work as representedby the nut or the tool as represented by the punch may be reciprocatedaxially with respect to the other.

Nuts constructed in accordance with this invention, when applied overand threaded home on bolt-stems and thelike, are effectively threadlocked thereon with a firm self-binding action under resilient tensionof a plurality of gripping members arranged in a manner to brake the nutagainst retrograde movement of either the nut or the stem to which it isapplied.

It will be seenthat the tool of this invention will produce the desireddeformation of the locking fingers I2 in a single movement of the tool,and that the fingers I2 can only assume the precise positionpredetermined by the shape and construction of the operative nutengaging portion of the tool.

Havlng'thus described the invention, whattis claimed is: I I

1. A forming tool for shaping resilient gripping fingers on a;self-binding nut, comprising a body having an axial bore opening to itswork engaging face, said face being countersunk around the bore, and thesurface of said countersunk portion being formed with an annular seriesof arcuate faces eccentric to the bore.

2. A forming toolfor shaping resilient'gripping fingers on aself-binding nut, comprising a body having an axial bore opening to itswork engaging face, said face being countersunk around the bore, thesurface of said countersunk portion being provided with an annularseries of arcuate faces eccentric to the bore, and said faces from theirouter to their inner ends being inclined axially and radially inwardlyof the bore at an angle of inclination progressively increased from oneside edge to the-other side edge of each.

' 3.'A forming tool for shaping resilient gripping fingers on aself-binding nut, comprising a body having an axial bore opening to itswork engaging face, said face being provided with an annular series ofarcuate portions axially conver'gent relative to the bore axis anddecreasingly eccentric thereto axially inwardly of the tool. 5

4. A, forming tool for shaping gripping portions of a self-binding nut,comprising a body having its work engaging fa'ce provided with a recess,the peripheral surface of said recess being provided with a series ofarcuate faces, the

' center of the arc of each face be ng spaced from the centers of thearcs of the other faces.

5. A forming tool for shaping gripping portions of a self-binding nut,comprising a body having its work engaging face provided with a recess,the peripheral surface of said recess being provided with a series ofarcuate faces, the center of the are of each face being spaced from thecenters of the arcs of the other faces, and said arcuate faces beingseparated by shoulders extending in a direction radially andsubstantially axially of the recess.

I 6. A forming tool for shaping the gripping portions of a self-bindingnut, comprising a body having a recess inits work-engaging face, theperipheral surface of said recess being provided with a series of faces,each face being offset at its ends from the adjacent faces to provideshoulders between the faces, each of said shoulders facing in the samedirection with respect to the periphery of the recess, and said facesfrom their outer to their inner ends being inclined axially and radiallyinwardly of the recess at an angle of inclination progressivelyincreased from one side edge to the other side edge of each face.

'7. A forming tool for shaping resilient gripping fingers on aself-binding nut, comprising a body having a recess in its work engagingface to receive the gripping fingers of the nut, said recess havinginwardly converging walls, said walls of the recess being provided witha series of axially and radially inclined faces, each face being oifsetat its ends from the adjacent faces to provide shoulders between thefaces, each of said shoulders facing in the same direction with respectto the periphery of the recess and each of said faces being of a size toengage one of the gripping fingers of the nut whereby, when the nut ismoved into the recess each finger will be bent inwardly and twistedabout one of its ends as an axis while the end of the finger serving asits twisting axis is maintained against outward movement by thecorresponding face of the recess.

8. A forming tool for shaping spaced resilient gripping fingers on aself-binding nut, comprising a body having a substantially circularrecess in its work engaging face to receive the gripping fingers of thenut, said recess having inwardly converging walls, the walls of therecess being provided with an annular series of ai-cua te faceseccentric to said recess, each of said faces being of a size to engageone of the gripping fingers of the nut, whereby each finger will be bentinwardly and twisted about one of its ends as an axis when the tool ismoved axially of the nut, the end of the finger serving as its twistingaxis being maintained against radially outward movement by thecorresponding arcuate face.

9. A forming tool for shaping spaced resilient gripping fingers on aself-binding nut, comprising a body having a substantially circularrecess in its work engaging face to receive the gripping fingers of thenut, said recess having inwardly converging walls. the walls of therecess being provided with an annular series of arcuate faces eccentricto said recess, each of said faces being of a size to engage one of thegripping fingers of the nut, whereby each finger will be bent inwardlyand twisted about one of its ends as an axis when the tool is movedaxially of the nut, the end of the finger serving as its twisting axisbeing maintained against radially outward movement by the correspondingarcuate face, and shoulders separating the arcuate faces and extendingsubstantially axially of the recess, said should'ers being adapted to bereceived in the spaces between the gripping fingers to prevent relativerotation between the tool and nut.

CLARE L. BRACKE'IT.

